Latest ArticlesThe hunt for agents that are suitable for actinide decorporation to reduce the whole-body load of actinide in accidental internal exposure is the ever-lasting goal in radiation protection and medical treatment in nuclear emergency. All current decorporation agents can be categorized as two groups, one is the molecular ligands, and the other is the nanoparticles decorated with molecular ligands. Here in this work, functional nanodiamonds (fNDs) with ssDNA (the endogenous biomacromolecule rich in phosphate groups) loaded on the NDs is reported, which poses good uranyl adsorption selectivity, high cellular uptake, fast excretion, and effective decorporation of uranyl from rat renal proximal tubular epithelial cells (NRK-52E). All those results corroborate that fNDs can potentially serve as a brand new family of chelators for actinide decorporation.
The complexation of pentavalent neptunium, Np(V), with nitrate ion in an ionic liquid solution has been studied spectroscopically for the first time. The characteristic f-f transition absorption band of Np(V) in the NIR region changes significantly upon the titration of nitrate ion into the solution, revealing strong complexation of Np(V) with nitrate ion in the ionic liquid. Most notably, the absorption band of Np(V) almost disappears when a sufficiently high concentration of nitrate ion is present in the solution. Such a rare optically "silent" species can be assigned to the 1:2 Np(V)/nitrate complex with a centrosymmetric coordination environment where Np sits at the inversion center.
Thioredoxin reductase 1 (TrxR1) is over activity in tumor cell to maintain their redox balance. Although gold clusters have great potential in antitumor drug as they could well inhibit TrxR1, the molecular mechanism has not been disclosed yet. In this work, we revealed gold clusters can well inhibit the activity of TrxR1 in lung tumor cells and further disclosed the inhibition mechanism by using computational simulation methods. We firstly inferred the binding sites of gold in the hydrophobic cavities on TrxR1. The simulation results show that the gold ion (released from Au cluster) interact with –SH of Cys189 in TrxR1, this greatly increase the distance between the C-terminal redox center of TrxR1 and the Trx redox center, thereby destroy the electron transfer pathway between them. Our electron transfer destroying mechanism is different from the previous hypothesis that gold binds to the Sec498 of TrxR1 which has never been proved by experimental and theory studies. This work provides a new understanding of the gold clusters to inhibit TrxR1 activity.
The treatment of anionic 99TcO4- in the waste tank with high alkalinity is still very challenging. In this work, a new temperature-responsive alkaline aqueous biphasic system (ABS) based on (tri-n-butyl)-n-tetradecyl phosphonium chloride (P44414Cl) was developed to remove radioactive 99TcO4-. The phase transition mechanism was studied by cloud point titration, small-angel X-ray scattering, dynamic light scattering, and molecular dynamic simulations. As the NaOH concentration or temperature increased, the P44414+ micelle could grow and aggregate. This micelle showed a particularly high affinity toward ReO4-/99TcO4- compared to other competing anions and could directly extract more than 98.6% of 99TcO4- from simulated radioactive tank waste supernatant. Furthermore, the loaded 99TcO4- could be easily stripped by using concentrated nitric acid rather than metal salt-based reductants. This work clearly demonstrates that the alkaline ABS is a promising separation system for solving the technetium problem in the alkaline waste tank.
Carbohydrate antigen 19-9 (CA19-9) with multi epitopes relatively high expresses on colorectal cancer (CRC) cells, making it an attractive target for developing radioimmunotherapy (RIT) for CRC. The lutetium-177 (177Lu) labeled monoclonal antibodies (mAbs) can selectively bind the corresponding antigens and release targeted cytotoxic radiation, which could induce cell apoptosis and reduce the drug-induced resistance. Here, a series of CA19-9 mAbs were labeled with zirconium-89 (89Zr), and one with high tumor uptake was screened via PET imaging, which has potential application for the diagnosis of CRC. Then the screened mAb (C003) labeled with 177Lu was utilized for CA19-9 targeted RIT, which presents a significant suppression effect on the growth of colo205 xenografts than immunotherapy alone. Meanwhile, the side effects of 177Lu-DOTA-C003 are limited according to the results of in vivo study. Both 89Zr-DFO-C003 for CRC immune-PET imaging and 177Lu-DOTA-C003 for RIT against CRC exhibit good potential in clinical applications.
Nitrogen enrichment and increased nitrogen content is an effective strategy for enhancing adsorption of uranium by carbon nitride polymers. Herein, we reported the uranium absorption by using a structurally well-defined and nitrogen-rich carbon nitride polymer with C3N5 stoichiometry for the first time. In comparison with the adsorption performance of g-C3N4 for U(VI), the conjugation system of the material was increased by connecting the heptazine unit through the azo bridge in the structure of C3N5, so that C3N5 exhibited several times higher adsorption performance than that of g-C3N4. The C3N5 has high kinetics for uranyl ions, which can adsorb 100 mg/g U(VI) in only 10 min and reach complete adsorption equilibrium in 60 min; the theoretical maximum adsorption capacity is 207 mg/g, meanwhile, the material exhibits high selectivity. The results of spectral analysis and theoretical calculations indicate that the process of uranyl ion capture by C3N5 is a combination of physical and chemical adsorption, and its higher density of electronic states makes the electrostatic binding ability enhanced, which is favorable to the adsorption of uranyl ions by C3N5. This work indicates that C3N5 has great promise and application in the separation and enrichment of uranyl ions, and also provides a reference for the systematic investigation of the adsorption ability of nitrogen-rich carbon nitrogen polymers on uranyl ions.
The development of uranyl ion detection technology has exhibited its significance in public security and environmental fields for the radioactivity and chemical toxicity of uranyl ion. The WHO standard of uranyl ion makes it necessary to develop highly sensitive uranyl rapid warning system in drinking water monitoring. Herein, a visualized rapid warning system for trace uranyl ion is carried out based on electrochemiluminescence (ECL) imaging technology to give an ultra-low limit of detection (LOD) and high selectivity. Amidoxime, a bi-functional group with both uranyl ion capturing and co-reactive functions, is modified on a conjugated polymer backbone with strong ECL signal to be prepared into three-in-one polymer nanoparticles (PNPs) with self-enhanced ECL property. The captured uranyl ion can enhance the ECL signal of PNPs via resonance energy transfer process to give the LOD as 0.5 ng/L, which is much lower than the known luminescent uranyl sensors. Furthermore, ECL imaging technology is introduced into realizing visualized uranyl rapid warning, and can be successfully applied on natural water samples. This study provides a novel strategy for uranyl rapid warning, and shows its potential meaning in public security and environmental fields.
Phototheranostics have attracted tremendous attention in cancer diagnosis and treatment because of the noninvasiveness and promising effectiveness. Developing advanced phototheranostic agents with long emission wavelength, excellent biocompatibility, great tumor-targeting capability, and efficient therapeutic effect is highly desirable. However, the mutual constraint between imaging and therapeutic functions usually hinders their wide applications in biomedical field. To balance this contradiction, we herein rationally designed and synthesized three novel tumor-targeted NIR-II probes (QR-2PEG321, QR-2PEG1000, and QR-2PEG5000) by conjugating three different chain lengths of PEG onto an integrin αvβ3-targeted NIR-II heptamethine cyanine fluorophore, respectively. In virtue of the essential amphiphilic characteristics of PEG polymers, these probes display various degree of aggregation in aqueous buffer accompanying with differential NIR-II imaging and photothermal (PTT) therapeutic performance. Both in vitro and in vivo results have demonstrated that probe QR-2PEG5000 has the best NIR-II imaging performance with prominent renal clearance, whereas QR-2PEG321 possesses excellent photoacoustic signal as well as PTT effect, which undoubtedly provides a promising toolbox for tumor diagnosis and therapy. We thus envision that these synthesized probes have great potential to be explored as a toolkit for precise diagnosis and treatment of malignant tumors.
Two tetravalent uranium silicate and germanate M2UIVT3O9 (M = K, Cs; T = Si, Ge) crystals were crystalized under inert gas by molten salt flux growth method. K2USi3O9 (1) crystallizes in the monoclinic space group P121/n1 with lattice parameters a = 7.1076 Å, b = 10.4776 Å, c = 12.2957 Å, γ = 120° and V = 915.67 Å3. Cs2UGe3O9 (2) crystallizes in a hexagonal space group P-6 with lattice constants of a = 7.5138 Å, b = 7.5138 Å, c = 11.0114 Å, γ = 120° and V = 538.38 Å3. Bond valence calculations indicate tetravalent uranium in both structures, which contain three-membered single-ring T3O96− trimers. K2USi3O9 is the first uranium silicate that contains the Si3O96− trimers.
The prevalence of positron emission tomography (PET) imaging has advanced biomedical applications for its ultrahigh sensitivity, deep tissue penetration and quantitative visualization of diseases in vivo. 64Cu with ideal half-life and decay characteristics has been designed as radioactive probes for disease diagnosis. The currently reported 64Cu-labeled nanomaterials have the advantages of long circulation time in serum, good biocompatibility and mature preparation methods, and have been used in vivo PET imaging, biodistribution and pharmacokinetic monitoring, and imaging guided therapy. At the same time, suitable carrier characteristics and radiolabeling strategies are particularly important in the 64Cu PET imaging process. In this review, we summarize different imaging probe designs and 64Cu radiolabeling strategies, as well as their eventual applications in biomedicine. The potential challenges and prospects of 64Cu labeled nanomaterials are also described, which provides broad prospects for radiolabeling strategies and further applications.
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